1. Field of the Invention
The present invention relates generally to so-called horizontal bandsaw machines and, more particularly, to a lubricating apparatus for applying cutting lubricant to an endless bandsaw blade in horizontal bandsaw machines.
2. Description of the Prior Art
In horizontal bandsaw machines, an endless bandsaw blade is trained around a pair of bandsaw wheels which are mounted on a saw head assembly for rotation to drive the bandsaw blade for cutting operations. The bandsaw blade is slidably guided by a pair of saw-guide assemblies which are provided at opposite sides of the cutting zone of the machine so that its cutting edge, when passing through the cutting zone, may be kept perpendicular to a work-table on which workpieces to be cut are placed. Also, the saw head assembly carrying the bandsaw wheels is so mounted as to be lowered towards the work-table so that the bandsaw blade may cut the workpieces placed on the work-table.
Since high-speed cutting is an important duty of the horizontal bandsaw machines, it is necessary that the bandsaw blade be lubricated with cutting lubricant at the cutting zone of the machine to minimize its friction with the workpieces being cut. Unless the bandsaw blade is lubricated, it will be worn out early because of the friction and the heat caused thereby during cutting operations. When the bandsaw blade becomes worn, of course, the cutting rate and accuracy will be greatly reduced, and furthermore the workpieces being cut will be subject to undesirable work hardening.
Conventionally, in order to lubricate the bandsaw blade in the horizontal bandsaw machines, the saw-guide assemblies for guiding the bandsaw blade at the opposite sides of the cutting zone are so designed as to apply the cutting lubricant to the bandsaw blade. Thus, the bandsaw blade is lubricated just before cutting into the workpieces being cut in order to minimize its friction, and it is also flooded with lubricant after having cut through the workpieces mainly for the purpose of washing off cutting chips. In this manner, the bandsaw blade is lubricated with less problems by the saw-guide assembly which guides the bandsaw blade just before cutting into the workpieces, for as long a time as the bandsaw blade is cutting workpieces which are small in size and are not difficult to cut.
In the conventional manner, however, the bandsaw blade cannot be lubricated sufficiently enough to cut large workpieces which are too large in cross section to be cut by the bandsaw blade. Difficulties with regard to the conventional manner are due to the fact that the bandsaw blade is lubricated only by the saw-guide assembly which guides the bandsaw blade before it cuts into the workpieces. Needless to say, the larger the workpieces to be cut, the more the bandsaw blade has to cut through the workpieces, and the larger amount of cutting lubricant is necessary to cut large workpieces. In this regard, the bandsaw blade cannot be sufficiently lubricated in the conventional manner, since the cutting lubricant is supplied to minimize the friction of the bandsaw blade mainly only by one of the saw-guide assemblies, namely, that assembly utilized for guiding the bandsaw blade before cutting into the workpieces. Also, the cutting lubricant which is applied by the saw-guide assembly to the bandsaw blade will be lost when the bandsaw blade is cutting the initial portion of the large workpieces and the cutting lubricant cannot be maintained thereafter on the bandsaw blade in order to continue to minimize the friction caused by the bandsaw blade.
In order to overcome the above described disadvantages, some horizontal bandsaw machines are provided with a midway lubricating means for applying the cutting lubricant to the bandsaw blade between the two saw-guide assemblies. In this case, however, a problem is that such a midway lubricating means should be so disposed that it will never be brought into collision with workpieces placed on the work-table, since the workpieces will come in between the two saw-guide assemblies as the saw head assembly is lowered to cut the workpieces. Therefore, there have been some horizontal bandsaw machines in which the midway lubricating means is fixedly mounted at a position duly apart from the run-way of the bandsaw blade so that it will never be touched by the largest workpieces that can be cut by the machine. As another problem, however, it is desirable that the midway lubricating means be arranged as near as possible to the workpieces being cut so as to effectively apply the cutting lubricant to the bandsaw blade. Also, it is necessary that the midway lubricating means be so provided that it may apply the cutting lubricant to the top of the back edge of the bandsaw blade so as to lubricate both sides of the bandsaw equally. For these reasons, in some horizontal bandsaw machines, a midway lubricating means using, for example, a flexible tube is adjustably provided in a manner such that the midway lubricating means can be adjusted with regard to its position depending upon sizes of workpieces to be cut. In this case, however, of course it is very troublesome to adjust the position of the midway lubricating means each time when it is desired to cut different sizes of workpieces. Furthermore, the midway lubricating means, even if properly set at the beginning, will get out of position because of vibrations during cutting operations and will cease to properly apply the cutting lubricant to the bandsaw blade.